Despite insignificant OS difference between the HER2-0 and HER2-low groups, the former exhibited superior DFS to the latter in the overall, HR-positive, and lymph node-negative populations, which was further confirmed by multifactorial analysis, suggesting the possibility of HER2-low as an inferior prognostic factor of breast carcinomas at an early stage. This evidence concerns the gene ERBB2 and breast carcinoma.